Used printer cartridges of fax machines, copiers, inkjet printers, and laser printers are often remanufactured. Printer cartridges typically include a toner hopper, a waste hopper, primary charge roller or PCR, a developer roller, and a drum. Generally, printers embed toner on paper by relying on electrical charges occurring within the printer cartridges. The toner is typically stored in the toner hopper and carries a negative charge. The drum is typically given a charge by the PCR. The charge of the drum is typically more positive than the charge of the toner, and thus the drum is able to attract the toner. Once the drum is given a charge by the PCR and a print pattern is set, the drum gets coated with toner. The drum that is coated with toner then rolls over a sheet of paper, which is usually given a negative charge by the PCR. The charge of the paper is less negative than the charge of the toner, and thus the paper attracts the toner. The toner is embedded on the paper according to the print pattern.
The drum is usually one of the components that wears out from usage and gets replaced during remanufacturing. The drum is typically attached to a drum axle, which is attached to a motor of the printer and allows the motor to rotate the drum. In some cartridges, the drum is attached to the drum axle with a mechanical spring pin that is inserted through a portion of the drum and a portion of the drum axle. Examples of these cartridges include cartridges for Hewlett-Packard laser printer model numbers 3000, 3500, 3600, 3700, and 3800.
To detach the drums from the drum axles of the above cartridges, a hammer and a chisel is conventionally used. The chisel is first aligned with the mechanical spring pin. Once the chisel is aligned, a hammer is used to cause the chisel to drive the mechanical spring pin out of the drum and the drum axle thereby allowing the drum to be detached from the cartridge. Other methods of detaching the drums include using a punch in lieu of the chisel. The punch may include a flatter head than the chisel, which provides a wider surface of pin contact than the chisel. Consequently, the punch may more effectively contact and drive the mechanical spring pin out of the drum and the drum axle than the chisel.
At least one problem with the conventional methods and tools is that they expose the drum to being damaged. For instance, the drum may include drum hubs made of soft plastic. Since irregular force is applied to the drum hub by the hammer, the chisel, or the punch, the soft plastic of the drum hub may be deformed. Another problem with the conventional tools is that they do not ease the step of aligning the mechanical spring pin with the device used to drive the mechanical spring pin out of the drum and the drum axle. The chisel or the punch may contact the mechanical spring pin, but may easily slip from the mechanical spring pin. Yet another problem with the conventional tools is that they only provide leverage in detaching the drum from the cartridge. The conventional tools do not provide leverage when a drum needs to be attached to the cartridge. Thus, the conventional methods and tools may not be desirable in high volume cartridge remanufacturing environments. Methods and apparatus for efficiently and quickly detaching the drums from the cartridges and reattaching the same are desired and are addressed by the present invention.